The present invention relates to piezo oscillators, and particularly to piezo oscillators with the start-up time taken to reach the steady oscillating state from the non-oscillating state shortened.
To make longer continuous use of cell phones possible, the crystal oscillators used as the reference oscillation source in cell phones are intermittently put into operation to reduce power consumption.
For crystal oscillators thus intermittently put into operation, the start-up time taken to generate desired output signals from beginning to be driven is desired to be short. Therefore, the crystal oscillator of the configuration disclosed in the patent application laid open under Laid Open No. 1996-51017 has been put into practical use.
FIG. 38 is a schematic diagram of the conventional crystal oscillator with an improved start-up characteristics, disclosed in the above gazette.
The crystal oscillator 100 shown in the figure is a typical Colpitts crystal oscillator, but characterized in the configuration in which one terminal of the crystal resonator 103 is connected to the base of a transistor 100 through a capacitor 102, and the other terminal of the crystal resonator 103 is connected to the power supply voltage Vcc line. Since the power supply voltage Vcc line is usually connected to the ground through a capacitor 104 of a comparatively large capacitance, the terminal of the crystal oscillator 103 connected to the power supply voltage Vcc line is also connected to the ground via the power supply voltage Vcc line.
Further, in this configuration, resistors 105 and 106 are base-biasing circuit, resistor 107 is an emitter resistor of the transistor 101, and capacitors 108 and 109 serve as part of load capacitance.
By this configuration, a voltage of the same level as the power supply voltage Vcc is applied to the crystal resonator 103 like a pulse wave, and the crystal resonator 103 vibrates in a large level of vibration. As a result, the start-up time taken for the oscillation signal to reach the required level becomes shorter.
However, in the crystal oscillator of the configuration described above, the power supply voltage Vcc line is contained in the oscillation loop, and hence noises contained in the supply voltage and those that come in via the power supply voltage Vcc line are directly applied to the crystal oscillator 103. The phase noise characteristics of this crystal resonator therefore can degrade because of the influence of noises.
Specifically, although the capacitor 104 connected between the power supply voltage Vcc line and the ground serves as a bypass capacitor in the crystal oscillator 100 of the configuration described above, it is not possible to completely remove the noises that comes in from the supply voltage and everywhere on the power supply voltage Vcc line even by using a plurality of bypass capacitors.
Since the noises are amplified by the amplification circuit in the oscillating circuit and output along with the oscillation signal, they can cause the degradation of the phase noise characteristics of the crystal oscillator 100.
If the output signal of such a crystal oscillator is used for digital processing, there is the possibility that bit errors occur in data processing because of the noise signals mixed in the output signal.
Further, when this crystal oscillator is built in apparatuses such as cell phones, the stray capacitance of other circuits connected to the power supply voltage Vcc line comes into the oscillation loop, and causes the problem that the oscillation frequency shifts from the set frequency.
Specifically, in addition to the capacitance of the capacitors and the stray capacitance associated with the circuit elements and wiring patterns of the crystal oscillator, the capacitance of the bypass capacitors connected to the power supply voltage Vcc line and the stray capacitance of circuits in the apparatus in which the crystal oscillator is built in, the oscillation frequency of the crystal oscillator 100 must be set taking into account the capacitance in the apparatus beforehand.
However, this adjustment method can lower the productivity of the apparatuses in which the crystal oscillator is used, since the capacitance of bypass capacitor used in apparatuses differs with models, and hence the adjustment condition must be change accordingly.
The present invention is made to solve these problems with conventional piezo oscillators. The object of the present invention is therefore to provide piezo oscillators having an improved start-up characteristics without degradation in the phase noise characteristics and the frequency stability characteristics.
The above object is accomplished by the following piezo oscillators.
The piezo oscillator of first embodiment is characterized in that: the piezo oscillator contains a crystal resonator, amplifying circuit, and quick start-up circuit; the quick start-up circuit has a configuration in which an NPN transistor is connected between the power supply voltage Vcc line and one terminal of the crystal resonator in forward polarity, and a capacitor is connected between the power supply voltage Vcc line and the base of the NPN transistor; and a start-up quickening voltage is applied to the piezo resonator from the power supply voltage Vcc line through the NPN transistor for a predetermined length of time after the application of power supply voltage Vcc.
The piezo oscillator of second embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit; the quick start-up circuit has a configuration in which a first NPN transistor is connected between the power supply voltage Vcc line and one terminal of the piezo resonator in forward polarity, a resistor is connected between the base and the emitter of the first NPN transistor, a second NPN transistor is connected to the power supply voltage Vcc line and the base of the first NPN transistor in forward polarity, and a capacitor is connected between the power supply voltage Vcc line and the base of the second NPN transistor; and a start-up quickening voltage is applied to the piezo resonator from the power supply voltage Vcc line through the NPN transistor for a predetermined length of time after the application of power supply voltage Vcc.
The piezo oscillator of third embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit; the quick start-up circuit has a configuration in which a PNP transistor is connected between the power supply voltage Vcc line and one terminal of the piezo resonator in forward polarity, and a capacitor and a diode are connected in parallel between the base of the PNP transistor and the ground; and a start-up quickening voltage is applied to the piezo resonator from the power supply voltage Vcc line through the NPN transistor for a predetermined length of time after the application of power supply voltage Vcc.
The piezo oscillator of fourth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; and the quick start-up circuit begins to operate with a delay determined according to the rise of voltage of the power supply voltage Vcc after the application of the power supply voltage Vcc and outputs the start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc.
The piezo oscillator of fifth embodiment is characterized in that: the piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit having a transistor switch and a voltage dividing circuit for base biasing of the transistor switch; and the quick start-up circuit begins to operate at the timing controlled by the voltage division ratio of the voltage dividing circuit after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc.
The piezo oscillator of sixth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit having a configuration in which a PNP transistor switch is connected between the oscillation loop of the piezo oscillator and the power supply voltage Vcc line with the collector and emitter in forward polarity, a first capacitor is connected between the base of the transistor and the power supply voltage Vcc line, and a second capacitor is connected between the base of the transistor and the ground; and the quick start-up circuit begins to operate with a delay determined according to the rise of the power supply voltage Vcc after the application of power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc.
The piezo oscillator of seventh embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a configuration in which a PNP transistor switch is connected between the oscillation loop of the piezo oscillator and the power supply voltage Vcc line with the collector and emitter in forward polarity, a first capacitor is connected between the base of the transistor and the power supply voltage Vcc line, and a second capacitor is connected between the base of the transistor and the ground; and the quick start-up circuit begins to operate at the timing controlled by the voltage division ratio of the voltage dividing circuit after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc.
The piezo oscillator of eighth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a first transistor switch, a voltage dividing circuit for base biasing of the first transistor switch, and a second transistor switch which is turned ON and OFF by the output current of the first transistor switch; and the quick start-up circuit begins to operate at the timing controlled by the voltage division ratio of the voltage dividing circuit after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc.
The piezo oscillator of ninth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a first PNP transistor switch connected between the oscillation loop of the piezo oscillator and the power supply voltage Vcc line with the collector and emitter in forward polarity, a first capacitor connected between the base of the first PNP transistor and the power supply voltage Vcc line, a second capacitor connected between the base of the first PNP transistor and the ground, and a second transistor switch which is turned ON and OFF by the output current of the first PNP transistor switch; and the quick start-up circuit begins to operate with a delay according to the rise of the power supply voltage Vcc after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc.
The piezo oscillator of tenth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a first PNP transistor switch connected between the oscillation loop of the piezo oscillator and the power supply voltage Vcc line with the collector and emitter in forward polarity, a first capacitor connected between the base of the first PNP transistor and the power supply voltage Vcc line, a second capacitor connected between the base of the first PNP transistor and the ground, and a second transistor switch which is turned ON and OFF by the output current of the first PNP transistor switch; and the quick start-up circuit begins to operate at the timing controlled by the capacitance ratio of the first and second capacitors after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc.
The piezo oscillator of eleventh embodiment is characterized in that: the oscillating circuit contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a first PNP transistor switch connected between the oscillation loop of the piezo oscillator and the power supply voltage Vcc line with the collector and emitter in forward polarity, a first capacitor connected between the base of the first PNP transistor and the power supply voltage Vcc line, and a second capacitor connected between the base of the first PNP transistor and the ground; the quick start-up circuit begins to operate with a delay according to the rise of the power supply voltage Vcc after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc; and the quick start-up circuit further has a transistor switch which turns ON at about the same time as the turning-ON of the first PNP transistor between the base of the first PNP transistor and the ground.
The piezo oscillator of twelfth embodiment is characterized in that: the oscillating circuit contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a first PNP transistor switch connected between the oscillation loop of the piezo oscillator and the power supply voltage Vcc line with the collector and emitter in forward polarity, a first capacitor connected between the base of the first PNP transistor and the power supply voltage Vcc line, and a second capacitor connected between the base of the first PNP transistor and the ground; the quick start-up circuit begins to operate with a delay according to the rise of the power supply voltage Vcc after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc; and the quick start-up circuit has a PNP transistor which turns ON at about the same time at the timing of the turning-ON of the first PNP transistor between the base of the first PNP transistor and the ground; the quick start-up circuit begins to operate at the timing controlled by the capacitance ratio of the first and second capacitors after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc; and the quick start-up circuit further has a transistor switch which turns ON at about the same time as the turning-ON of the first PNP transistor between the base of the first PNP transistor and the ground.
The piezo oscillator of thirteenth embodiment is characterized in that: the oscillating circuit contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a first PNP transistor switch connected between the oscillation loop of the piezo oscillator and the power supply voltage Vcc line with the collector and emitter in forward polarity, a first capacitor connected between the base of the first PNP transistor and the power supply voltage Vcc line, a second capacitor connected between the base of the first PNP transistor and the ground, and a second transistor switch which is turned ON and OFF by the output current of the first PNP transistor switch; the quick start-up circuit begins to operate with a delay according to the rise of the power supply voltage Vcc after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc; and the quick start-up circuit further has a transistor switch which turns ON at about the same time as the turning-ON of the first PNP transistor between the base of the first PNP transistor and the ground.
The piezo oscillator of fourteenth embodiment is characterized in that: the oscillating circuit contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a first PNP transistor switch connected between the oscillation loop of the piezo oscillator and the power supply voltage Vcc line with the collector and emitter in forward polarity, a first capacitor connected between the base of the first PNP transistor and the power supply voltage Vcc line, a second capacitor connected between the base of the first PNP transistor and the ground, and a second transistor switch which is turned ON and OFF by the output current of the first PNP transistor switch; the quick start-up circuit begins to operate at the timing controlled by the capacitance ratio of the first and second capacitors after the application of the power supply voltage Vcc and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc; and the quick start-up circuit further has a transistor switch which turns ON at about the same time as the turning-ON of the first PNP transistor between the base of the first PNP transistor and the ground.
The piezo oscillator of fifteenth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, amplifying circuit, and quick start-up circuit for applying a start-up quickening voltage of a desired level to one terminal of the piezo resonator after the application of power supply voltage Vcc; the quick start-up circuit has a transistor switch and a voltage dividing circuit for base biasing of the transistor switch which has a series circuit of a capacitor and a resistor; and the quick start-up circuit begins to operate at the timing controlled by the time constant of the series circuit and outputs a start-up quickening voltage with a steeper rise than the rise characteristics of the power supply voltage Vcc.
The piezo oscillator of sixteenth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, and quick start-up circuit; and the quick start-up circuit functions to increase the collector current of the oscillating transistor for a predetermined length of time after the application of power supply voltage Vcc in order to shorten the start-up time of the crystal oscillating circuit and stops functioning after the predetermined length of time.
The piezo oscillator of seventeenth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor connected between the emitter of the oscillating transistor and the ground, and quick start-up circuit; and the quick start-up circuit functions to decrease the impedance across the emitter resistor for a predetermined length of time after the application of power supply voltage Vcc in order to shorten the start-up time of the piezo oscillator.
The piezo oscillator of eighteenth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor connected between the emitter of the oscillating transistor and the ground, and quick start-up circuit; and the quick start-up circuit contains a switch circuit and connects both ends of the emitter resistor by the switch circuit for a predetermined length of time after the application of power supply voltage Vcc to decrease the resistance between the emitter of the oscillating transistor and the ground and shorten the start-up time of the piezo oscillator.
The piezo oscillator of nineteenth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor connected between the emitter of the oscillating transistor and the ground, and quick start-up circuit; and the quick start-up circuit contains a switch circuit and a switch control circuit, and the switch control circuit controls the ON and OFF operation of the switch circuit according to the charging current of a capacitor to short-circuit both ends of the emitter resistor by the switch circuit for a predetermined length of time after the application of power supply voltage Vcc and thereby decrease the resistance between the emitter of the oscillating transistor and the ground and shorten the start-up time of the piezo oscillator.
The piezo oscillator of twentieth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor connected between the emitter of the oscillating transistor and the ground, and quick start-up circuit; the quick start-up circuit contains a switch circuit and a switch control circuit; the switch circuit contains a second transistor whose collector is connected to the emitter of the oscillating transistor and whose emitter is connected to the ground; the switch control circuit contains a third transistor whose collector is connected to the power supply voltage Vcc line, whose base is connected to the power supply voltage Vcc line through a capacitor, and whose emitter is connected to the base of the second transistor through a resistor; and the ON and OFF operation of the switch circuit is controlled by the charging current of the capacitor so as to short-circuit both ends of the emitter resistor for a predetermined length of time after the application of the power supply voltage Vcc and thereby decrease the resistance between the emitter of the oscillating transistor and the ground and shorten the start-up time of the piezo oscillator.
The piezo oscillator of twenty first embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor connected between the emitter of the oscillating transistor and the ground, and quick start-up circuit; the quick start-up circuit contains a switch circuit and a switch control circuit; the switch circuit contains a second transistor whose collector is connected to the emitter of the oscillating transistor through a resistor and whose emitter is connected to the ground; the switch control circuit contains a third transistor whose collector is connected to the power supply voltage Vcc line, whose base is connected to the power supply voltage Vcc line through a capacitor, and whose emitter is connected to the base of the second transistor through a resistor; and the ON and OFF operation of the switch circuit is controlled by the charging current of the capacitor so as to short-circuit both ends of the emitter resistor for a predetermined length of time after the application of the power supply voltage Vcc and thereby decrease the resistance between the emitter of the oscillating transistor and the ground and shorten the start-up time of the piezo oscillator.
The piezo oscillator of twenty second embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, and quick start-up circuit; and the quick start-up circuit functions to pull up the voltage of the collector of the oscillating transistor for a predetermined length of time after the application of power supply voltage Vcc and thereby increase the collector current and shorten the start-up time of the piezo oscillator, and stops functioning after the predetermined length of time.
The piezo oscillator of twenty third embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor connected between the collector of the second transistor and the power supply voltage Vcc line, and quick start-up circuit; the quick start-up circuit functions to pull up the collector voltage of the second transistor for a predetermined length of time after the application of power supply voltage Vcc; and the resulting rise in the collector voltage of the oscillating transistor causes an increase in the collector current of the oscillating transistor which makes the piezo resonator begin to vibrate forcibly and thereby shortens the start-up time of the piezo oscillator.
The piezo oscillator of twenty fourth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor connected between the collector of the second transistor and the power supply voltage Vcc line, and quick start-up circuit; the quick start-up circuit contains a switch circuit; the switch circuit turns ON for a predetermined length of time after the application of power supply voltage Vcc to connect the collector of the oscillating transistor or the collector of the second transistor to the power supply voltage Vcc line with a small resistance; and the resulting rise in the collector voltage of the oscillating transistor causes an increase in the collector current of the oscillating transistor which makes the piezo resonator begin to vibrate forcibly and thereby shortens the start-up time of the piezo oscillator.
The piezo oscillator of twenty fifth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor connected between the collector of the second transistor and the power supply voltage Vcc line, and quick start-up circuit; the quick start-up circuit contains a switch circuit and a switch control circuit; the switch control circuit contains a capacitor and is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuit ON; the switch circuit, while it is ON, connects the collector of the oscillating transistor or the collector of the second transistor to the power supply voltage Vcc line with a small resistance; and the resulting rise in the collector voltage of the oscillating transistor causes an increase in the collector current of the oscillating transistor which makes the piezo resonator begin to vibrate forcibly and thereby shortens the start-up time of the piezo oscillator.
The piezo oscillator of twenty sixth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor connected between the collector of the second transistor and the power supply voltage Vcc line, and quick start-up circuit; the quick start-up circuit contains a switch circuit and a switch control circuit; the switch circuit has a configuration in which the emitter of a PNP transistor is connected to the power supply voltage Vcc line, the collector of the PNP transistor is connected to the collector of the oscillating transistor or to the collector of the second transistor; the switch control circuit has a configuration in which the collector of a third transistor is connected to the base of the PNP transistor, the base of the third transistor is connected to the power supply voltage Vcc line through a capacitor and to the ground through a diode in reverse polarity, and the emitter of the third transistor is connected to the ground through a resistor; the switch control circuit is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuit ON; the switch circuit, while it is ON, connects the collector of the oscillating transistor or the collector of the second transistor to the power supply voltage Vcc line with a small resistance; and the resulting rise in the collector voltage of the oscillating transistor causes an increase in the collector current of the oscillating transistor which makes the piezo resonator begin to vibrate forcibly and thereby shortens the start-up time of the piezo oscillator.
The piezo oscillator of twenty seventh embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor connected between the collector of the second transistor and the power supply voltage Vcc line, and quick start-up circuit; the quick start-up circuit contains a switch circuit and a switch control circuit; the switch circuit has a configuration in which the emitter of a PNP transistor is connected to the power supply voltage Vcc line, the collector of the PNP transistor is connected to the collector of the oscillating transistor or the collector of the second transistor; the switch control circuit has a configuration in which the collector of a third transistor is connected to the base of the PNP transistor and to the power supply voltage Vcc line through a resistor, the base of the third transistor is connected to the power supply voltage Vcc line through a capacitor and to the ground through a diode in reverse polarity, and the emitter of the third transistor is connected to the ground through a resistor; the switch control circuit is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuit ON; the switch circuit, while it is ON, connects the collector of the oscillating transistor or the collector of the second transistor to the power supply voltage Vcc line with a small resistance; and the resulting rise in the collector voltage of the oscillating transistor causes an increase in the collector current of the oscillating transistor which makes the piezo resonator begin to vibrate forcibly and thereby shortens the start-up time of the piezo oscillator.
The piezo oscillator of twenty eighth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor and collector resistor of the oscillating transistor, and quick start-up circuit; the quick start-up circuit functions to connect the emitter of the oscillating transistor to the ground with a small resistance and connect the collector of the oscillating transistor to the power supply voltage Vcc line for a predetermined length of time after the application of the power supply voltage Vcc, and the resulting increase in the collector current of the oscillating transistor shortens the start-up time of the piezo oscillator; and the quick start-up circuit stops functioning after the predetermined length of time, and the collector current of the oscillating transistor decreases to the normal value.
The piezo oscillator of twenty ninth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor, and quick start-up circuit; the quick start-up circuit functions to connect the emitter of the oscillating transistor to the ground with a small resistance and connect the collector of the oscillating transistor or of the second transistor to the power supply voltage Vcc line with a small resistance for a predetermined length of time after the application of the power supply voltage Vcc, which causes an increase in the collector current of the oscillating transistor and thereby shortens the start-up time of the piezo oscillator; and the quick start-up circuit stops functioning after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirtieth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor and collector resistor of the oscillating transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits: one switch circuit connects the emitter of the oscillating transistor to the ground with a small resistance, and the other switch circuit connects the collector of the oscillating transistor to the power supply voltage Vcc line with a small resistance; the switch circuits of the quick start-up circuit are turned ON for a predetermined length of time after the application of power supply voltage Vcc, and the resulting increase in the collector current of the oscillating transistor shortens the start-up time of the piezo oscillator; and the switch circuits of the quick start-up circuit are turned off after the predetermined length of time, and the collector current of the oscillating transistor decreases to the normal value.
The piezo oscillator of thirty first embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits: one switch circuit connects the emitter of the oscillating transistor to the ground with a small resistance, and the other switch circuit connects the collector of the oscillating transistor or of the second transistor to the power supply voltage Vcc line with a small resistance; the switch circuits of the quick start-up circuit are turned ON for a predetermined length of time after the application of power supply voltage Vcc, and the resulting increase in the collector current of the oscillating transistor shortens the start-up time of the piezo oscillator; and the switch circuits of the quick start-up circuit are turned off after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirty second embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor and collector resistor of the oscillating transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits and a switch control circuit; the switch control circuit contains a capacitor and is activated to turn the switching circuits ON by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc; when being ON, one of the switch circuits connects the emitter of the oscillating transistor to the ground with a small resistance, and the other switch circuit connects the collector of the oscillating transistor to the power supply voltage Vcc line with a small resistance, which causes an increase in the collector current of the oscillating transistor and thereby shortens the start-up time of the piezo oscillator; and the switch circuits are turned off after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirty third embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits and a switch control circuit; the switch control circuit contains a capacitor and is activated to turn the switching circuits ON by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc; when being ON, one of the switch circuits connects the emitter of the oscillating transistor to the ground with a small resistance, and the other switch circuit connects the collector of the oscillating transistor or of the second transistor to the power supply voltage Vcc line with a small resistance, which causes an increase in the collector current of the oscillating transistor and thereby shortens the start-up time of the piezo oscillator; and the switch circuits are turned off after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirty fourth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor and collector resistor of the oscillating transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits and a switch control circuit; one of the switch circuits has a configuration in which the collector of a second transistor is connected to the emitter of the oscillating transistor and the emitter of the second transistor is connected to the ground; the other switch circuit has a configuration in which the emitter of a PNP transistor is connected to the power supply voltage Vcc line and the collector of the PNP transistor is connected to the collector of the oscillating transistor; the switch control circuit has a configuration in which the emitter of a third transistor is connected to the base of the second transistor through a resistor, the collector of the third transistor is connected to the base of the PNP transistor, and the base of the third transistor is connected to the power supply voltage Vcc line through a capacitor and to the ground through a diode in reverse polarity; the switch control circuit is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuits ON; the switch circuits, when being ON, connect the emitter of the oscillating transistor to the ground with a small resistance and connect the collector of the oscillating transistor to the power supply voltage Vcc line with a small resistance; and the switch circuits are turned off by the switch control circuit after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirty fifth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits and a switch control circuit; one of the switch circuits has a configuration in which the collector of a third transistor is connected to the emitter of the oscillating transistor and the emitter of the third transistor is connected to the ground; the other switch circuit has a configuration in which the emitter of a PNP transistor is connected to the power supply voltage Vcc line and the collector of the PNP transistor is connected to the collector of the oscillating transistor or the collector of the second transistor; the switch control circuit has a configuration in which the emitter of a fourth transistor is connected to the base of the third transistor through a resistor, the collector of the fourth transistor is connected to the base of the PNP transistor, and the base of the fourth transistor is connected to the power supply voltage Vcc line through a capacitor and to the ground through a diode in reverse polarity; the switch control circuit is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuits ON; the switch circuits, when being ON, connect the emitter of the oscillating transistor to the ground with a small resistance and connect the collector of the oscillating transistor or of the second transistor to the power supply voltage Vcc line with a small resistance; and the switch circuits are turned off by the switch control circuit after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirty sixth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor and collector resistor of the oscillating transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits and a switch control circuit; one of the switch circuits has a configuration in which the collector of a second transistor is connected to the emitter of the oscillating transistor and the emitter of the second transistor is connected to the ground; the other switch circuit has a configuration in which the emitter of a PNP transistor is connected to the power supply voltage Vcc line and the collector of the PNP transistor is connected to the collector of the oscillating transistor; the switch control circuit has a configuration in which the emitter of a third transistor is connected to the base of the second transistor through a resistor, the collector of the third transistor is connected to the base of the PNP transistor and to the power supply voltage Vcc line through a resistor, and the base of the third transistor is connected to the power supply voltage Vcc line through a capacitor and to the ground through a diode in reverse polarity; the switch control circuit is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuits ON; the switch circuits, when being ON, connect the emitter of the oscillating transistor to the ground with a small resistance and connect the collector of the oscillating transistor to the power supply voltage Vcc line with a small resistance; and the switch circuits are turned off by the switch control circuit after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirty seventh embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits and a switch control circuit; one of the switch circuits has a configuration in which the collector of a third transistor is connected to the emitter of the oscillating transistor and the emitter of the third transistor is connected to the ground; the other switch circuit has a configuration in which the emitter of a PNP transistor is connected to the power supply voltage Vcc line and the collector of the PNP transistor is connected to the collector of the oscillating transistor or the collector of the second transistor; the switch control circuit has a configuration in which the emitter of a fourth transistor is connected to the base of the third transistor through a resistor, the collector of the fourth transistor is connected to the base of the PNP transistor and to the power supply voltage Vcc line through a resistor, and the base of the fourth transistor is connected to the power supply voltage Vcc line through a capacitor and to the ground through a diode in reverse polarity; the switch control circuit is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuits ON; the switch circuits, when being ON, connect the emitter of the oscillating transistor to the ground with a small resistance and connect the collector of the oscillating transistor or of the second transistor to the power supply voltage Vcc line with a small resistance; and the switch circuits are turned off by the switch control circuit after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirty eighth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor and collector resistor of the oscillating transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits and a switch control circuit; one of the switch circuits has a configuration in which the collector of a second transistor is connected to the emitter of the oscillating transistor through a resistor and the emitter of the second transistor is connected to the ground; the other switch circuit has a configuration in which the emitter of a PNP transistor is connected to the power supply voltage Vcc line and the collector of the PNP transistor is connected to the collector of the oscillating transistor; the switch control circuit has a configuration in which the emitter of a third transistor is connected to the base of the second transistor through a resistor, the collector of the third transistor is connected to the base of the PNP transistor and to the power supply voltage Vcc line through a resistor, and the base of the third transistor is connected to the power supply voltage Vcc line through a capacitor and to the ground through a diode in reverse polarity; the switch control circuit is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuits ON; the switch circuits, when being ON, connect the emitter of the oscillating transistor to the ground with a small resistance and connect the collector of the oscillating transistor to the power supply voltage Vcc line with a small resistance; and the switch circuits are turned off by the switch control circuit after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of thirty ninth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor, second transistor connected to the oscillating transistor in cascade, collector resistor of the second transistor, and quick start-up circuit; the quick start-up circuit has at least two switch circuits and a switch control circuit; one of the switch circuits has a configuration in which the collector of a third transistor is connected to the emitter of the oscillating transistor through a resistor and the emitter of the third transistor is connected to the ground; the other switch circuit has a configuration in which the emitter of a PNP transistor is connected to the power supply voltage Vcc line and the collector of the PNP transistor is connected to the collector of the oscillating transistor or the collector of the second transistor; the switch control circuit has a configuration in which the emitter of a fourth transistor is connected to the base of the third transistor through a resistor, the collector of the fourth transistor is connected to the base of the PNP transistor and to the power supply voltage Vcc line through a resistor, and the base of the fourth transistor is connected to the power supply voltage Vcc line through a capacitor and to the ground through a diode in reverse polarity; the switch control circuit is activated by the charging current of the capacitor for a predetermined length of time after the application of power supply voltage Vcc to turn the switch circuits ON; the switch circuits, when being ON, connect the emitter of the oscillating transistor to the ground with a small resistance and connect the collector of the oscillating transistor or of the second transistor to the power supply voltage Vcc line with a small resistance; and the switch circuits are turned off by the switch control circuit after the predetermined length of time to let the collector current of the oscillating transistor decrease to the normal value.
The piezo oscillator of fortieth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, and quick start-up circuit; and the quick start-up circuit controls the collector current and the emitter current of the oscillating transistor by means of current regulating circuits in a current mirror configuration only for a predetermined length of time after the application of the power supply voltage Vcc.
The piezo oscillator of forty first embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, and two quick start-up circuits; a first quick start-up circuit applies a start-up quickening voltage to the piezo resonator only for a predetermined length of time after the application of the power supply voltage Vcc; and a second quick start-up circuit increases the collector current of the oscillating transistor only for a predetermined length of time after the application of the power supply voltage Vcc.
The piezo oscillator of forty second embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, and two quick start-up circuits; the quick start-up circuits each have one or more switch circuits; a first quick start-up circuit applies the power supply voltage Vcc to the piezo resonator as a start-up quickening voltage through the switch circuit only for a predetermined length of time after the application of the power supply voltage Vcc; and a second quick start-up circuit bypasses the emitter resistor, the collector resistor, or both of the oscillating transistor through the switch circuit or switch circuits to increase the collector current of the oscillating transistor only for a predetermined length of time after the application of the power supply voltage Vcc.
The piezo oscillator of forty third embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, buffer transistor connected to the oscillating transistor in cascade; the base of the buffer transistor is connected to the power supply voltage Vcc line through a first capacitor; and the base of the buffer transistor is connected to the ground through a second capacitor.
The piezo oscillator of forty fourth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor, and quick start-up circuit; the quick start-up circuit has a switch circuit using a depletion type p-channel FET for the switch device; the switch circuit turns ON only for a predetermined length of time after the application of power supply voltage Vcc to connect both ends of the emitter resistor and thereby increase the start-up current to the piezo resonator; and the switch circuit turns OFF after the predetermined length of time.
The piezo oscillator of forty fifth embodiment is characterized in that: the piezo oscillator contains a piezo resonator, oscillating transistor, emitter resistor of the oscillating transistor, and quick start-up circuit; the quick start-up circuit has a configuration in which the base of a depletion type p-channel FET is connected to the power supply voltage Vcc line, the gate of the depletion type p-channel FET is connected to between a resistor and a capacitor connected in series between the power supply voltage Vcc line and the ground, and the source to drain of the depletion type p-channel FET is connected in parallel with the emitter resistor of the oscillating transistor; the depletion type p-channel FET turns ON only for a predetermined length of time after the application of power supply voltage Vcc to connect both ends of the emitter resistor and thereby increase the start-up current to the piezo resonator; and the depletion type p-channel FET turns OFF after the predetermined length of time.